Scotland's rejection of independence from Britain will help forge a "united, open and stronger" European Union, European Commission president Jose Manuel Barroso said on Friday.

Barroso, who heads the executive branch of the 28-member EU, said Brussels would carry on a "constructive dialogue" with Scotland, which has limited powers, after voters said no to ending the 307-year-old union.

"I welcome the decision of the Scottish people to maintain the unity of the United Kingdom. This outcome is good for the united, open and stronger Europe that the European Commission stands for," Barroso said in a statement.

He said the commission welcomed the fact that during the independence debate "the Scottish Government and the Scottish people have repeatedly reaffirmed their European commitment."

"The European Commission will continue to engage in a constructive dialogue with the Scottish Government, in areas under its responsibility, that are important to Scotland's future, including jobs and growth, energy, climate change and the environment, and smarter regulation."

Barroso had previously warned Scotland that it would have to reapply for membership of the EU if it became an independent state, and angered Scottish nationalists by saying that the process would likely be difficult.